Arrays & Strings

Arrays and Strings

How arrays are laid out in memory, which operations are cheap, and the traversal patterns you will reuse everywhere.

Two Pointers Technique

Solve array problems in linear time by walking two indices toward each other instead of using nested loops.

Sliding Window Technique

Maintain a moving range over an array to answer subarray questions in a single pass.

Kadane's Algorithm and Prefix Sum Tricks

Find the best contiguous subarray without checking every one, using a habit of thought you will reuse in dozens of problems.